The problem was introduced in 5.5.20 by Bug 13116225. It tried to
protect against downgrading from a version 5.6.4 database that was
created with a page size other than 16k. Version 5.6.4 supports
page sizes 4k and 8k and stamps that page size into the header page
of each tablespace file. Version 5.5.20 attempts to read that page
size in the file header.
But it turns out that only the first system tablespace file has a
reliable flags field in the header. So only ibdata1 can be or needs
to be tested for another page size. Extra system tablespace files
like ibdata2, ibdata3, etc do not and should not be tested since the
flags field is unreliable.
This fix does not remove the underlying cause of the assertion
failure. It just works around the problem, allowing a corrupted
secondary index to be fixed by DROP INDEX and CREATE INDEX (or in the
worst case, by re-creating the table).
ibuf_delete(): If the record to be purged is the last one in the page
or it is not delete-marked, refuse to purge it. Instead, write an
error message to the error log and let a debug assertion fail.
ibuf_set_del_mark(): If the record to be delete-marked is not found,
display some more information in the error log and let a debug
assertion fail.
row_undo_mod_del_unmark_sec_and_undo_update(),
row_upd_sec_index_entry(): Let a debug assertion fail when the record
to be delete-marked is not found.
buf_page_print(): Add ut_ad(0) so that corruption will be more
prominent in stress testing with debug binaries. Add ut_ad(0) here and
there where corruption is noticed.
btr_corruption_report(): Display some data on page_is_comp() mismatch.
btr_assert_not_corrupted(): A wrapper around btr_corruption_report().
Assert that page_is_comp() agrees with the table flags.
rb:911 approved by Inaam Rana
This bug ensures that a live downgrade from an InnoDB 5.6 with WL5756 and
a database created with innodb-page-size=8k or 4k will make a version 5.5
installation politely refuse to start. Instead of crashing or giving some
indication about a corrupted database, it will indicate the page size
difference.
This patch takes only that part of the Wl5756 patch that is needed to
protect against opening a tablespace that is stamped with a different
page size.
It also contains the change in dict_index_find_on_id_low() just in case
a database with another page size is created by recompiling a pre-WL5756
InnoDB.
The innoDB global variable srv_lower_case_table_names is set to the value of lower_case_table_names declared in mysqld.h server in ha_innodb.cc. Since this variable can change at runtime, it is reset for each handler call to ::create, ::open, ::rename_table & ::delete_table.
But it is possible for tables to be implicitly opened before an explicit handler call is made when an engine is first started or restarted. I was able to reproduce that with the testcase in this patch on a version of InnoDB from 2 weeks ago. It seemed like the change buffer entries for the secondary key was getting put into pages after the restart. (But I am not sure, I did not write down the call stack while it was reproducing.) In the current code, the implicit open, which is actually a call to dict_load_foreigns(), does not occur with this testcase.
The change is to replace srv_lower_case_table_names by an interface function in innodb.cc that retrieves the server global variable when it is needed.
SRV_CONC_FORCE_EXIT_INNODB
This is a bogus UNIV_SYNC_DEBUG assertion failure that I introduced
when introducing assertions for checking that InnoDB is not holding
any mutexes or rw-locks when returning control to MySQL.
srv_suspend_mysql_thread(): Release dict_operation_lock before
invoking srv_conc_force_exit_innodb(), which would now check that the
thread is not holding any mutexes or rw-locks. After resuming, check
sync_thread_levels_nonempty_trx() and do srv_conc_force_enter_innodb()
before reacquiring the dict_operation_lock.
rb:646 approved by Sunny Bains
On shutdown, do not exit threads in os_event_wait(). This method of
exiting was only used by the I/O handler threads. Exit them on a
higher level.
os_event_wait_low(), os_event_wait_time_low(): Do not exit on shutdown.
os_thread_exit(), ut_dbg_assertion_failed(), ut_print_timestamp(): Add
attribute cold, so that GCC knows that these functions are rarely
invoked and can be optimized for size.
os_aio_linux_collect(): Return on shutdown.
os_aio_linux_handle(), os_aio_simulated_handle(), os_aio_windows_handle():
Set *message1 = *message2 = NULL and return TRUE on shutdown.
fil_aio_wait(): Return on shutdown.
logs_empty_and_mark_files_at_shutdown(): Even in very fast shutdown
(innodb_fast_shutdown=2), allow the background threads to exit, but
skip the flushing and log checkpointing.
innobase_shutdown_for_mysql(): Always wait for all the threads to exit.
rb:633 approved by Sunny Bains
Remove most references to thread id in InnoDB. Three references
remain: the current holder of a mutex, and the current x-lock holder
of a rw-lock, and some references in UNIV_SYNC_DEBUG checks. This
allows MySQL to change the thread associated to a client connection.
Tighten the UNIV_SYNC_DEBUG checks, trying to ensure that no InnoDB
mutex or x-lock is being held when returning control to MySQL. The
only semaphore that may be held is the btr_search_latch in shared mode.
sync_thread_levels_empty_except_dict(): A wrapper for
sync_thread_levels_empty_gen(TRUE).
sync_thread_levels_nonempty_trx(): Check that the current thread is
not holding any InnoDB semaphores, except btr_search_latch if
trx->has_search_latch.
sync_thread_levels_empty(): Unused function; remove.
trx_t: Remove mysql_thread_id and mysql_process_no.
srv_slot_t: Remove id and handle.
row_search_for_mysql(), srv_conc_enter_innodb(),
srv_conc_force_enter_innodb(), srv_conc_force_exit_innodb(),
srv_conc_exit_innodb(), srv_suspend_mysql_thread: Assert
!sync_thread_levels_nonempty_trx().
rb:634 approved by Sunny Bains
sync_array_print_long_waits(): Return the longest waiting thread ID
and the longest waited-for lock. Only if those remain unchanged
between calls in srv_error_monitor_thread(), increment
fatal_cnt. Otherwise, reset fatal_cnt.
Background: There is a built-in watchdog in InnoDB whose purpose is to
kill the server when some thread is stuck waiting for a mutex or
rw-lock. Before this fix, the logic was flawed.
The function sync_array_print_long_waits() returns TRUE if it finds a
lock wait that exceeds 10 minutes (srv_fatal_semaphore_wait_threshold).
The function srv_error_monitor_thread() will kill the server if this
happens 10 times in a row (fatal_cnt reaches 10), checked every 30
seconds. This is wrong, because this situation does not mean that the
server is hung. If the server is very busy for a little over 15
minutes, it will be killed.
Consider this example. Thread T1 is waiting for mutex M. Some time
later, threads T2..Tn start waiting for the same mutex M. If T1 keeps
waiting for 600 seconds, fatal_cnt will be incremented to 1. So far,
so good. Now, if M is granted to T1, the server was obviously not
stuck. But, T2..Tn keeps waiting, and their wait time will be longer
than 600 seconds. If 5 minutes later, some Tn has still been waiting
for more than 10 minutes for the mutex M, the server can be killed,
even though it is not stuck.
rb:622 approved by Jimmy Yang
ibuf_inside(), ibuf_enter(), ibuf_exit(): Add the parameter mtr. The
flag is no longer kept in the thread-local storage but in the
mini-transaction (mtr->inside_ibuf).
mtr_start(): Clean up the comment and remove the unused return value.
mtr_commit(): Assert !ibuf_inside(mtr) in debug builds.
ibuf_mtr_start(): Like mtr_start(), but sets the flag.
ibuf_mtr_commit(), ibuf_btr_pcur_commit_specify_mtr(): Wrappers that
assert ibuf_inside().
buf_page_get_zip(), buf_page_init_for_read(),
buf_read_ibuf_merge_pages(), fil_io(), ibuf_free_excess_pages(),
ibuf_contract_ext(): Remove assertions on ibuf_inside(), because a
mini-transaction is not available.
buf_read_ahead_linear(): Add the parameter inside_ibuf.
ibuf_restore_pos(): When this function returns FALSE, it commits mtr
and must therefore do ibuf_exit(mtr).
ibuf_delete_rec(): This function commits mtr and must therefore do
ibuf_exit(mtr).
ibuf_rec_get_page_no(), ibuf_rec_get_space(), ibuf_rec_get_info(),
ibuf_rec_get_op_type(), ibuf_build_entry_from_ibuf_rec(),
ibuf_rec_get_volume(), ibuf_get_merge_page_nos(),
ibuf_get_volume_buffered_count(), ibuf_get_entry_counter_low(): Add
the parameter mtr in debug builds, for asserting ibuf_inside(mtr).
rb:585 approved by Sunny Bains
Remove the slot_no member of struct thr_local_struct.
enum srv_thread_type: Remove unused thread types.
srv_get_thread_type(): Unused function, remove.
thr_local_get_slot_no(), thr_local_set_slot_no(): Remove.
srv_thread_type_validate(), srv_slot_get_type(): New functions, for debugging.
srv_table_reserve_slot(): Return the srv_slot_t* directly. Do not create
thread-local storage.
srv_suspend_thread(): Get the srv_slot_t* as parameter. Return void;
the caller knows slot->event already.
srv_thread_has_reserved_slot(), srv_release_threads(): Assert
srv_thread_type_validate(type).
srv_init(): Use mem_zalloc() instead of mem_alloc(). Replace
srv_table_get_nth_slot(), because it now asserts that the kernel_mutex
is being held.
srv_master_thread(), srv_purge_thread(): Remember the slot from
srv_table_reserve_slot().
rb:629 approved by Inaam Rana
Bug #11766501: Multiple RBS break the get rseg with mininum trx_t::no code during purge
Bug# 59291 changes:
Main problem is that truncating the UNDO log at the completion of every
trx_purge() call is expensive as the number of rollback segments is increased.
We truncate after a configurable amount of pages. The innodb_purge_batch_size
parameter is used to control when InnoDB does the actual truncate. The truncate
is done once after 128 (or TRX_SYS_N_RSEGS iterations). In other words we
truncate after purge 128 * innodb_purge_batch_size. The smaller the batch
size the quicker we truncate.
Introduce a new parameter that allows how many rollback segments to use for
storing REDO information. This is really step 1 in allowing complete control
to the user over rollback space management.
New parameters:
i) innodb_rollback_segments = number of rollback_segments to use
(default is now 128) dynamic parameter, can be changed anytime.
Currently there is little benefit in changing it from the default.
Optimisations in the patch.
i. Change the O(n) behaviour of trx_rseg_get_on_id() to O(log n)
Backported from 5.6. Refactor some of the binary heap code.
Create a new include/ut0bh.ic file.
ii. Avoid truncating the rollback segments after every purge.
Related changes that were moved to a separate patch:
i. Purge should not do any flushing, only wait for space to be free so that
it only does purging of records unless it is held up by a long running
transaction that is preventing it from progressing.
ii. Give the purge thread preference over transactions when acquiring the
rseg->mutex during commit. This to avoid purge blocking unnecessarily
when getting the next rollback segment to purge.
Bug #11766501 changes:
Add the rseg to the min binary heap under the cover of the kernel mutex and
the binary heap mutex. This ensures the ordering of the min binary heap.
The two changes have to be committed together because they share the same
that fixes both issues.
rb://567 Approved by: Inaam Rana.
rb://566
approved by: Sunny
When using native aio on linux each IO helper thread should be able to
handle upto 256 IO requests. The number 256 is the same which is used
for simulated aio as well. In case of windows where we also use native
aio this limit is 32 because of OS constraints. It seems that we are
using the limit of 32 for all the platforms where we are using native
aio. The fix is to use 256 on all platforms except windows (when native
aio is enabled on windows)
"rows examined" estimates". This change implements "innodb_stats_method"
with options of "nulls_equal", "nulls_unequal" and "null_ignored".
rb://553 approved by Marko
Check whether the master and purge thread are active after creating them. Do
not proceed until both threads have started. We do this by checking whether a
slot has been reserved by both the respective threads.
Add srv_thread_has_reserved_slot() returns slot no or ULINT_UNDEFINED.
rb://536 Approved by Jimmy
InnoDB does not attempt to handle lower_case_table_names == 2 when looking
up foreign table names and referenced table name. It turned that server
variable into a boolean and ignored the possibility of it being '2'.
The setting lower_case_table_names == 2 means that it should be stored and
displayed in mixed case as given, but compared internally in lower case.
Normally the server deals with this since it stores table names. But
InnoDB stores referential constraints for the server, so it needs to keep
track of both lower case and given names.
This solution creates two table name pointers for each foreign and referenced
table name. One to display the name, and one to look it up. Both pointers
point to the same allocated string unless this setting is 2. So the overhead
added is not too much.
Two functions are created in dict0mem.c to populate the ..._lookup versions
of these pointers. Both dict_mem_foreign_table_name_lookup_set() and
dict_mem_referenced_table_name_lookup_set() are called 5 times each.
Fix a race condition in srv_master_thread(). We need to acquire the kernel
mutex before calling srv_table_reserve_slot(). Add a mutex_own() assertion
in srv_table_reserve_slot().
Add new function os_cond_wait_timed(). Change the os_thread_sleep() calls
to timed conditional waits. Signal the background threads during the shutdown
phase so that we avoid waiting for the sleep to timeout thus saving some time.
rb://439 -- Approved by Jimmy Yang
Issue an error message to the error log when
trx->dict_operation_lock_mode == RW_X_LATCH in
srv_suspend_mysql_thread(). Transactions that modify InnoDB
data dictionary tables must be free of lock waits, because they
must be holding the data dictionary latch in exclusive mode.
The transactions must not be accessing any other tables other than
the data dictionary tables.
The handling of RW_X_LATCH was accidentally added in the InnoDB Plugin,
as a wrong fix of an assertion failure. (Fast index creation was accessing
both data dictionary tables and user tables in the same transaction.)
Silence the UNIV_SYNC_DEBUG assertion failure while upgrading old data files
to multiple rollback segments during server startup. Because the upgrade
takes place while InnoDB is running a single thread, we can safely ignore the
latching order checks without fearing deadlocks.
innobase_start_or_create_for_mysql(): Set srv_is_being_started = FALSE
only after trx_sys_create_rsegs() has completed.
sync_thread_add_level(): If srv_is_being_started, ignore latching order
violations for SYNC_TRX_SYS_HEADER and SYNC_IBUF_BITMAP.
Create all the non-IO threads after creating the extra rollback segments.
Patch originally from Marko with some additions by Sunny.
This patch was originally developed by Vladislav Vaintroub.
The main changes are:
* Use TryEnterCriticalSection in os_fast_mutex_trylock().
* Use lightweight condition variables on Vista or later Windows;
but fall back to events on older Windows, such as XP.
This patch also fixes the following bugs:
bug# 52102 InnoDB Plugin shows performance drop compared to InnoDB
on Windows
bug# 53204 os_fastmutex_trylock is implemented incorrectly on Windows
rb://363 approved by Inaam Rana
